Kanneliya rain forest (Kanneliya-Dediyagala-Nakiyadeniya) or KDN is a forest complex with high importance, located in southern Sri Lanka. And same times KDN is one of the least known natural jewels in the island and seldom included as an important site of the visit in most Sri Lanka road trips.
The forest complex designated as a biosphere reserve in 2004 by UNESCO. The KDN complex is the second largest rainforest in Sri Lanka after Sinharaja forest reserve. This forest area has been identified as one of the richest areas with flowering plants in South Asia. The forest complex is situated 35 km northwest of the city of Galle. The rainforest is a major catchment area for two of the most important rivers in southern Sri Lanka, the Gin and Nilwala Rivers. Like Sinharaaja KDN forest complex provides shelter to a large number of animal, plants and trees species. The number of Endemic Fauna and flora species within the forest is very high compared to most rainforests in Sri Lanka.
The biosphere consists of series of parallel mountain ranges and valleys. The elevation ranges from 60 m to 425 m above the sea level. Mean annual temperature is 27.0°C while annual temperature variation is 4°C-5°C.
The forest complex is playing an important role as a catchment area for many rivers and streams that flow through the area. Kanneli, Nanikiththa and Udugama are the smaller streams of Kanneliya, while Homa dola and Gal bandi dola are sourced from Nakiyadeniya and Dediyagala.
The KDN forest complex shows a high degree of floral endemism and as much as 17% of lowland endemic floral species are confined to this forest area. Of 319 woody plants recorded in the area, about 52% is endemic to the country. The main category of the vegetation of KDN complex represents Sri Lanka lowland rain forests. The floral communities dominated by Shorea-Dipterocarpus-Mesua (Sinhalese “Doona-Hora-Na”) are common in the emergent layer of the forest.
Numerous medicinal plants are found in these forests. They include Concinium fenestratum (Sinhalese “Weniwelgata”), Salacia reticulate (“Kothala Himbutu”), and Tinospora cordifolia (“Rasakinda”), Lycopodium Squarrosum (“Kuda hadaya”) and Lycopodium phlegmaria (“Maha hadaya”) are among the rare plants the forest complex harbours.
Some 220 fauna species recorded from KDN and surrounding areas. This includes 41 endemic species. The forest complex is home to 86 species mammals. This includes 4 species of shrews, 5 species of rodents, one carnivore and 2 primates. Out of 26 endemic birds of Sri Lanka, 20 of them can be seen in KDN forest complex. Sri Lanka Spurfowl, Sri Lanka Junglefowl, Sri Lanka Grey Hornbill, Red-faced Malkoha, Orange-billed Babbler, Sri Lanka Blue Magpie are several of them. 20% of Sri Lanka’s endemic freshwater fish species inhabit in the waters of Gin River and Nilwala River, which sourced by the springs of Kanneliya-Dediyagala-Nakiyadeniya. Among the forests of KDN there is a high concentration of snakes, there are 36 species of snakes, 17 of them are endemic species and belong to 6 families. A total of 23 species of Lizards recorded in these rain forests.
10,000 people live in 78 villages around the forest complex. Human activities within the forest reserve is a major threat to the existence of KDN forest complex. Collection of firewood, deforestation for cultivations of crops, using the forest reserve for animal husbandry is identified as the major threats.
Nugegoda, Rajagala and Dediyagala hermitages are situated within the forest. The forest complex was subjected to logging until it was suspended in 1988. Fortunately, the diversity of species and plants remains largely intact. A forest corridor between Sinharaja Forest Reserve and the KDN forest complex is being planned for facilitating animal movement between the two forests. Green-billed Coucal, Sri Lanka Blue Magpie, Ashy-headed Laughing thrush and White-faced Starling are endangered bird species that occurred very often in KDN. Twenty-seven percent of floral species in KDN are categorized as vulnerable while forty-five percent are in the rare plant categories.